This anthology includes fourteen of Crispin Wrights’s highly influential essays on the phenomenon of vagueness in natural language, collectively representing almost half a century of cutting-edge systematic research. Key issues addressed include whether or under what assumptions vague expressions’ apparent tolerance of marginal changes in things to which they apply indicates that they are governed by inconsistent semantic rules, the varieties of Sorites paradox and the roots of the plausibility of their respective major premises, what it is for something to be a borderline case of a vague expression, whether vagueness should be viewed as fundamentally a semantic or an epistemic phenomenon, whether there is ‘higher-order’ vagueness, and what should be the appropriate logic for vague statements. The essays reprinted here jointly document the development of a distinctively original treatment of the philosophy and logic of vagueness, broadly analogous to the intuitionistic philosophy and logic for pure mathematics. Richard Kimberly Heck contributes an extended introductory essay, providing both an insightful critical overview of the development of the distinctive elements of Wright’s thought about vagueness, and indeed an invaluable advanced introduction to the topic.